[PATCH 06/45] KVM: SVM: Add NMI injection support

[Avi Kivity <avi@redhat.com>]

From: Gleb Natapov <gleb@redhat.com>

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |    8 +++-
 arch/x86/kvm/svm.c              |   96 ++++++++++++++++++++-------------------
 arch/x86/kvm/vmx.c              |   79 ++++++++------------------------
 arch/x86/kvm/x86.c              |   71 ++++++++++++++++++++++++++++-
 4 files changed, 145 insertions(+), 109 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 53533ea..dd9ecd3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -512,10 +512,15 @@ struct kvm_x86_ops {
 				unsigned char *hypercall_addr);
 	int (*get_irq)(struct kvm_vcpu *vcpu);
 	void (*set_irq)(struct kvm_vcpu *vcpu, int vec);
+	void (*set_nmi)(struct kvm_vcpu *vcpu);
 	void (*queue_exception)(struct kvm_vcpu *vcpu, unsigned nr,
 				bool has_error_code, u32 error_code);
-	void (*inject_pending_irq)(struct kvm_vcpu *vcpu, struct kvm_run *run);
 	int (*interrupt_allowed)(struct kvm_vcpu *vcpu);
+	int (*nmi_allowed)(struct kvm_vcpu *vcpu);
+	void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
+	void (*enable_irq_window)(struct kvm_vcpu *vcpu);
+	void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
+	void (*drop_interrupt_shadow)(struct kvm_vcpu *vcpu);
 	int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
 	int (*get_tdp_level)(void);
 	int (*get_mt_mask_shift)(void);
@@ -763,6 +768,7 @@ enum {
 #define HF_GIF_MASK		(1 << 0)
 #define HF_HIF_MASK		(1 << 1)
 #define HF_VINTR_MASK		(1 << 2)
+#define HF_NMI_MASK		(1 << 3)
 
 /*
  * Hardware virtualization extension instructions may fault if a
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 0f53439..1807288 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1843,6 +1843,14 @@ static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 	return 1;
 }
 
+static int iret_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+	++svm->vcpu.stat.nmi_window_exits;
+	svm->vmcb->control.intercept &= ~(1UL << INTERCEPT_IRET);
+	svm->vcpu.arch.hflags &= ~HF_NMI_MASK;
+	return 1;
+}
+
 static int invlpg_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
 	if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0) != EMULATE_DONE)
@@ -1863,8 +1871,10 @@ static int cr8_write_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 	u8 cr8_prev = kvm_get_cr8(&svm->vcpu);
 	/* instruction emulation calls kvm_set_cr8() */
 	emulate_instruction(&svm->vcpu, NULL, 0, 0, 0);
-	if (irqchip_in_kernel(svm->vcpu.kvm))
+	if (irqchip_in_kernel(svm->vcpu.kvm)) {
+		svm->vmcb->control.intercept_cr_write &= ~INTERCEPT_CR8_MASK;
 		return 1;
+	}
 	if (cr8_prev <= kvm_get_cr8(&svm->vcpu))
 		return 1;
 	kvm_run->exit_reason = KVM_EXIT_SET_TPR;
@@ -2120,6 +2130,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
 	[SVM_EXIT_VINTR]			= interrupt_window_interception,
 	/* [SVM_EXIT_CR0_SEL_WRITE]		= emulate_on_interception, */
 	[SVM_EXIT_CPUID]			= cpuid_interception,
+	[SVM_EXIT_IRET]                         = iret_interception,
 	[SVM_EXIT_INVD]                         = emulate_on_interception,
 	[SVM_EXIT_HLT]				= halt_interception,
 	[SVM_EXIT_INVLPG]			= invlpg_interception,
@@ -2227,6 +2238,21 @@ static void pre_svm_run(struct vcpu_svm *svm)
 		new_asid(svm, svm_data);
 }
 
+static void svm_drop_interrupt_shadow(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
+}
+
+static void svm_inject_nmi(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI;
+	vcpu->arch.hflags |= HF_NMI_MASK;
+	svm->vmcb->control.intercept |= (1UL << INTERCEPT_IRET);
+	++vcpu->stat.nmi_injections;
+}
 
 static inline void svm_inject_irq(struct vcpu_svm *svm, int irq)
 {
@@ -2242,8 +2268,10 @@ static inline void svm_inject_irq(struct vcpu_svm *svm, int irq)
 		((/*control->int_vector >> 4*/ 0xf) << V_INTR_PRIO_SHIFT);
 }
 
-static void svm_queue_irq(struct vcpu_svm *svm, unsigned nr)
+static void svm_queue_irq(struct kvm_vcpu *vcpu, unsigned nr)
 {
+	struct vcpu_svm *svm = to_svm(vcpu);
+
 	svm->vmcb->control.event_inj = nr |
 		SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
 }
@@ -2254,28 +2282,26 @@ static void svm_set_irq(struct kvm_vcpu *vcpu, int irq)
 
 	nested_svm_intr(svm);
 
-	svm_queue_irq(svm, irq);
+	svm_queue_irq(vcpu, irq);
 }
 
-static void update_cr8_intercept(struct kvm_vcpu *vcpu)
+static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
-	struct vmcb *vmcb = svm->vmcb;
-	int max_irr, tpr;
 
-	if (!irqchip_in_kernel(vcpu->kvm) || vcpu->arch.apic->vapic_addr)
+	if (irr == -1)
 		return;
 
-	vmcb->control.intercept_cr_write &= ~INTERCEPT_CR8_MASK;
-
-	max_irr = kvm_lapic_find_highest_irr(vcpu);
-	if (max_irr == -1)
-		return;
-
-	tpr = kvm_lapic_get_cr8(vcpu) << 4;
+	if (tpr >= irr)
+		svm->vmcb->control.intercept_cr_write |= INTERCEPT_CR8_MASK;
+}
 
-	if (tpr >= (max_irr & 0xf0))
-		vmcb->control.intercept_cr_write |= INTERCEPT_CR8_MASK;
+static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	struct vmcb *vmcb = svm->vmcb;
+	return !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&
+		!(svm->vcpu.arch.hflags & HF_NMI_MASK);
 }
 
 static int svm_interrupt_allowed(struct kvm_vcpu *vcpu)
@@ -2293,39 +2319,12 @@ static void enable_irq_window(struct kvm_vcpu *vcpu)
 	svm_inject_irq(to_svm(vcpu), 0x0);
 }
 
-static void svm_intr_inject(struct kvm_vcpu *vcpu)
-{
-	/* try to reinject previous events if any */
-	if (vcpu->arch.interrupt.pending) {
-		svm_queue_irq(to_svm(vcpu), vcpu->arch.interrupt.nr);
-		return;
-	}
-
-	/* try to inject new event if pending */
-	if (kvm_cpu_has_interrupt(vcpu)) {
-		if (svm_interrupt_allowed(vcpu)) {
-			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu));
-			svm_queue_irq(to_svm(vcpu), vcpu->arch.interrupt.nr);
-		}
-	}
-}
-
-static void svm_intr_assist(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
+static void enable_nmi_window(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
-	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
-		kvm_run->request_interrupt_window;
 
-	if (nested_svm_intr(svm))
-		goto out;
-
-	svm_intr_inject(vcpu);
-
-	if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
+	if (svm->vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK)
 		enable_irq_window(vcpu);
-
-out:
-	update_cr8_intercept(vcpu);
 }
 
 static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
@@ -2650,9 +2649,14 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.patch_hypercall = svm_patch_hypercall,
 	.get_irq = svm_get_irq,
 	.set_irq = svm_set_irq,
+	.set_nmi = svm_inject_nmi,
 	.queue_exception = svm_queue_exception,
-	.inject_pending_irq = svm_intr_assist,
 	.interrupt_allowed = svm_interrupt_allowed,
+	.nmi_allowed = svm_nmi_allowed,
+	.enable_nmi_window = enable_nmi_window,
+	.enable_irq_window = enable_irq_window,
+	.update_cr8_intercept = update_cr8_intercept,
+	.drop_interrupt_shadow = svm_drop_interrupt_shadow,
 
 	.set_tss_addr = svm_set_tss_addr,
 	.get_tdp_level = get_npt_level,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 116eac0..bad2413 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1314,6 +1314,9 @@ static __init int hardware_setup(void)
 	if (!cpu_has_vmx_flexpriority())
 		flexpriority_enabled = 0;
 
+	if (!cpu_has_vmx_tpr_shadow())
+		kvm_x86_ops->update_cr8_intercept = NULL;
+
 	return alloc_kvm_area();
 }
 
@@ -2404,6 +2407,12 @@ out:
 	return ret;
 }
 
+void vmx_drop_interrupt_shadow(struct kvm_vcpu *vcpu)
+{
+	vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
+			GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS);
+}
+
 static void enable_irq_window(struct kvm_vcpu *vcpu)
 {
 	u32 cpu_based_vm_exec_control;
@@ -3214,21 +3223,14 @@ static int vmx_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 	return 0;
 }
 
-static void update_tpr_threshold(struct kvm_vcpu *vcpu)
+static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
 {
-	int max_irr, tpr;
-
-	if (!vm_need_tpr_shadow(vcpu->kvm))
-		return;
-
-	if (!kvm_lapic_enabled(vcpu) ||
-	    ((max_irr = kvm_lapic_find_highest_irr(vcpu)) == -1)) {
+	if (irr == -1 || tpr < irr) {
 		vmcs_write32(TPR_THRESHOLD, 0);
 		return;
 	}
 
-	tpr = (kvm_lapic_get_cr8(vcpu) & 0x0f) << 4;
-	vmcs_write32(TPR_THRESHOLD, (max_irr > tpr) ? tpr >> 4 : max_irr >> 4);
+	vmcs_write32(TPR_THRESHOLD, irr);
 }
 
 static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
@@ -3300,55 +3302,6 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
 	}
 }
 
-static void vmx_intr_inject(struct kvm_vcpu *vcpu)
-{
-	/* try to reinject previous events if any */
-	if (vcpu->arch.nmi_injected) {
-		vmx_inject_nmi(vcpu);
-		return;
-	}
-
-	if (vcpu->arch.interrupt.pending) {
-		vmx_inject_irq(vcpu, vcpu->arch.interrupt.nr);
-		return;
-	}
-
-	/* try to inject new event if pending */
-	if (vcpu->arch.nmi_pending) {
-		if (vmx_nmi_allowed(vcpu)) {
-			vcpu->arch.nmi_pending = false;
-			vcpu->arch.nmi_injected = true;
-			vmx_inject_nmi(vcpu);
-		}
-	} else if (kvm_cpu_has_interrupt(vcpu)) {
-		if (vmx_interrupt_allowed(vcpu)) {
-			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu));
-			vmx_inject_irq(vcpu, vcpu->arch.interrupt.nr);
-		}
-	}
-}
-
-static void vmx_intr_assist(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
-{
-	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
-		kvm_run->request_interrupt_window;
-
-	update_tpr_threshold(vcpu);
-
-	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
-		vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
-				GUEST_INTR_STATE_STI |
-				GUEST_INTR_STATE_MOV_SS);
-
-	vmx_intr_inject(vcpu);
-
-	/* enable NMI/IRQ window open exits if needed */
-	if (vcpu->arch.nmi_pending)
-		enable_nmi_window(vcpu);
-	else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
-		enable_irq_window(vcpu);
-}
-
 /*
  * Failure to inject an interrupt should give us the information
  * in IDT_VECTORING_INFO_FIELD.  However, if the failure occurs
@@ -3683,9 +3636,15 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.patch_hypercall = vmx_patch_hypercall,
 	.get_irq = vmx_get_irq,
 	.set_irq = vmx_inject_irq,
+	.set_nmi = vmx_inject_nmi,
 	.queue_exception = vmx_queue_exception,
-	.inject_pending_irq = vmx_intr_assist,
 	.interrupt_allowed = vmx_interrupt_allowed,
+	.nmi_allowed = vmx_nmi_allowed,
+	.enable_nmi_window = enable_nmi_window,
+	.enable_irq_window = enable_irq_window,
+	.update_cr8_intercept = update_cr8_intercept,
+	.drop_interrupt_shadow = vmx_drop_interrupt_shadow,
+
 	.set_tss_addr = vmx_set_tss_addr,
 	.get_tdp_level = get_ept_level,
 	.get_mt_mask_shift = vmx_get_mt_mask_shift,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4bd56c7..b3ecaf8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3110,6 +3110,68 @@ static void vapic_exit(struct kvm_vcpu *vcpu)
 	up_read(&vcpu->kvm->slots_lock);
 }
 
+static void update_cr8_intercept(struct kvm_vcpu *vcpu)
+{
+	int max_irr, tpr;
+
+	if (!kvm_x86_ops->update_cr8_intercept)
+		return;
+
+	max_irr = kvm_lapic_find_highest_irr(vcpu);
+
+	if (max_irr != -1)
+		max_irr >>= 4;
+
+	tpr = kvm_lapic_get_cr8(vcpu);
+
+	kvm_x86_ops->update_cr8_intercept(vcpu, tpr, max_irr);
+}
+
+static void inject_irq(struct kvm_vcpu *vcpu)
+{
+	/* try to reinject previous events if any */
+	if (vcpu->arch.nmi_injected) {
+		kvm_x86_ops->set_nmi(vcpu);
+		return;
+	}
+
+	if (vcpu->arch.interrupt.pending) {
+		kvm_x86_ops->set_irq(vcpu, vcpu->arch.interrupt.nr);
+		return;
+	}
+
+	/* try to inject new event if pending */
+	if (vcpu->arch.nmi_pending) {
+		if (kvm_x86_ops->nmi_allowed(vcpu)) {
+			vcpu->arch.nmi_pending = false;
+			vcpu->arch.nmi_injected = true;
+			kvm_x86_ops->set_nmi(vcpu);
+		}
+	} else if (kvm_cpu_has_interrupt(vcpu)) {
+		if (kvm_x86_ops->interrupt_allowed(vcpu)) {
+			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu));
+			kvm_x86_ops->set_irq(vcpu, vcpu->arch.interrupt.nr);
+		}
+	}
+}
+
+static void inject_pending_irq(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
+{
+	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
+		kvm_run->request_interrupt_window;
+
+	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+		kvm_x86_ops->drop_interrupt_shadow(vcpu);
+
+	inject_irq(vcpu);
+
+	/* enable NMI/IRQ window open exits if needed */
+	if (vcpu->arch.nmi_pending)
+		kvm_x86_ops->enable_nmi_window(vcpu);
+	else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
+		kvm_x86_ops->enable_irq_window(vcpu);
+}
+
 static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
 	int r;
@@ -3168,9 +3230,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	if (vcpu->arch.exception.pending)
 		__queue_exception(vcpu);
 	else
-		kvm_x86_ops->inject_pending_irq(vcpu, kvm_run);
+		inject_pending_irq(vcpu, kvm_run);
 
-	kvm_lapic_sync_to_vapic(vcpu);
+	if (kvm_lapic_enabled(vcpu)) {
+		if (!vcpu->arch.apic->vapic_addr)
+			update_cr8_intercept(vcpu);
+		else
+			kvm_lapic_sync_to_vapic(vcpu);
+	}
 
 	up_read(&vcpu->kvm->slots_lock);
 
-- 
1.6.0.6